C#使用接口的多重继承详细介绍

在多重继承中, 一个类可以具有多个父类, 并且可以从其所有父类继承功能。如下图所示, 类C继承了类A和B的功能。

但是C#不支持多类继承。为了克服这个问题, 我们使用接口来实现多个类的继承。借助接口, 类C(如上图所示)可以获得类A和B的功能。

示例1：首先, 我们尝试继承极客1和极客2类别转换为lsbin类别, 则编译器将给出错误信息, 因为C#直接不支持多个类继承。

//C# program to illustrate
//multiple class inheritance
using System;
using System.Collections;
  
//Parent class 1
class Geeks1 {
  
     //Providing the implementation
     //of languages() method
     public void languages()
     {
  
         //Creating ArrayList
         ArrayList My_list = new ArrayList();
  
         //Adding elements in the
         //My_list ArrayList
         My_list.Add( "C" );
         My_list.Add( "C++" );
         My_list.Add( "C#" );
         My_list.Add( "Java" );
  
         Console.WriteLine( "Languages provided by lsbin:" );
         foreach ( var elements in My_list)
         {
             Console.WriteLine(elements);
         }
     }
}
  
//Parent class 2
class Geeks2 {
  
     //Providing the implementation
     //of courses() method
     public void courses()
     {
  
         //Creating ArrayList
         ArrayList My_list = new ArrayList();
  
         //Adding elements in the
         //My_list ArrayList
         My_list.Add( "System Design" );
         My_list.Add( "Fork Python" );
         My_list.Add( "Geeks Classes DSA" );
         My_list.Add( "Fork Java" );
  
         Console.WriteLine( "\nCourses provided by lsbin:" );
         foreach ( var elements in My_list)
         {
             Console.WriteLine(elements);
         }
     }
}
  
//Child class
class lsbin : Geeks1, Geeks2 {
}
  
public class GFG {
  
     //Main method
     static public void Main()
     {
  
         //Creating object of lsbin class
         lsbin obj = new lsbin();
         obj.languages();
         obj.courses();
     }
}

运行时错误：

prog.cs(61, 30)：错误CS1721：'lsbin'：类不能具有多个基类('Geeks1'和'Geeks2')prog.cs(35, 7)：(与先前错误相关的符号位置)

但是我们可以使用接口将Geeks1和Geek2类的功能间接继承到lsbin类中。如下图所示。

示例2：都GFG1和GFG2接口由Geeks1和Geeks2类实现。现在, Geeks1和Geeks2类定义了language()和courses()方法。当lsbin类继承GFG1和GFG2接口时, 你无需重新定义语言()和培训班()方法只是简单地创建对象极客1和极客2上课并访问语言()和培训班()lsbin类中使用这些对象的方法。

//C# program to illustrate how to
//implement multiple class inheritance
//using interfaces
using System;
using System.Collections;
  
//Interface 1
interface GFG1 {
     void languages();
}
  
//Parent class 1
class Geeks1 : GFG1 {
  
     //Providing the implementation
     //of languages() method
     public void languages()
     {
  
         //Creating ArrayList
         ArrayList My_list = new ArrayList();
  
         //Adding elements in the
         //My_list ArrayList
         My_list.Add( "C" );
         My_list.Add( "C++" );
         My_list.Add( "C#" );
         My_list.Add( "Java" );
  
         Console.WriteLine( "Languages provided by lsbin:" );
         foreach ( var elements in My_list)
         {
             Console.WriteLine(elements);
         }
     }
}
  
//Interface 2
interface GFG2 {
     void courses();
}
  
//Parent class 2
class Geeks2 : GFG2 {
  
     //Providing the implementation
     //of courses() method
     public void courses()
     {
  
         //Creating ArrayList
         ArrayList My_list = new ArrayList();
  
         //Adding elements in the
         //My_list ArrayList
         My_list.Add( "System Design" );
         My_list.Add( "Fork Python" );
         My_list.Add( "Geeks Classes DSA" );
         My_list.Add( "Fork Java" );
  
         Console.WriteLine( "\nCourses provided by lsbin:" );
         foreach ( var elements in My_list)
         {
             Console.WriteLine(elements);
         }
     }
}
  
//Child class
class lsbin : GFG1, GFG2 {
  
     //Creating objects of Geeks1 and Geeks2 class
     Geeks1 obj1 = new Geeks1();
     Geeks2 obj2 = new Geeks2();
  
     public void languages()
     {
         obj1.languages();
     }
  
     public void courses()
     {
         obj2.courses();
     }
}
  
//Driver Class
public class GFG {
  
     //Main method
     static public void Main()
     {
  
         //Creating object of lsbin class
         lsbin obj = new lsbin();
         obj.languages();
         obj.courses();
     }
}

输出如下：

Languages provided by lsbin:
C
C++
C#
Java

Courses provided by lsbin:
System Design
Fork Python
Geeks Classes DSA
Fork Java

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